Please help me to calculate dilution rate for the developer

[mingaun]

Hello,

This is the first time I am developing film and I don't even know if my calculations are correct. This is to develop Adox CMS 20 using the Adotech developer. In order to increase the life span of the developer we need to add water the same amount as how much developer was taken out. The dilution rate are given as follows

Once opened, Adox Adotech Developer will last only 6 weeks before oxidizing.
It is recommended to add an equal amount of water to developer that is removed from the bottle to preserve the developer activity.*

With every following film being developed, the amount of developer concentrate used needs to be increased accordingly. *

Example to make 250 ml of final working solution (small tank):
first film 10ml of concentrate plus 240 ml of water,
second film 12.5 ml*plus*237.50*of water,
third film 16.5 ml*plus*233.50*of water,
fourth film 25 ml*plus*225 ml*of water,
last film all of the remaining diluted concentrate plus 200 ml*of water.

This will extend the developer life to 12 months.

Now all was clear until I realize that I need a total of 290ml of working solution to develop a single 35mm film in the Paterson tank. The above example given to me was using 250ml of working solution. My new calculations are as below

First film 11.6ml + 278.4ml water
Second film 14.5ml + 275.5ml water
Third film 19.14ml + 270.86ml water
Fourth film 29.0ml + 261ml water
Fifth film 58ml + 232ml water.

Obviously using this method I can only develop four films.

Is the calculations correct? Someone help me confirm them please.

Thank you
Mark Lim

 

[Rick A]

It appears that the dilutions are based on using a one reel ss tank. My simple solution to your dilema is to get a stainless steel single reel tank and one ss reel. These only require 8fl. ounces(237ml) of liquid to fill. This would leave you with extra, allowing for the fifth film.

 

[mingaun]

Rick, that's probably a good idea and helps save some developer fluid. But at this moment I already have one single reel and would like to use it first. Thanks for the idea.

Mark

 

[heespharm]

Sound like its an problem with it's reaction to air ... Instead put marbles in the bottle to reduce the amount of air in the bottle that way you'll never have to worry about these silly dilutions....


And when your done with this developer don't buy it ever again!!

 

[Rick A]

Sound like its an problem with it's reaction to air ... Instead put marbles in the bottle to reduce the amount of air in the bottle that way you'll never have to worry about these silly dilutions....


And when your done with this developer don't buy it ever again!!

Amen. If you want super fine grain, Adox CHS 25 art in D-76 1+1 or Pyrocat-HD 1+1+100(my preferred)

 

[piu58]

Dear Mark,

the calculation is simple.

The first film needs 1/5 of the dev, the second 1/4 of the remaining and so on.

That means, if you fill the empty space you have to take
10 ml
12,5 ml
16,7 ml
25 ml
50 ml

 

[mingaun]

Sound like its an problem with it's reaction to air ... Instead put marbles in the bottle to reduce the amount of air in the bottle that way you'll never have to worry about these silly dilutions....


And when your done with this developer don't buy it ever again!!

It is a problem with air and your solution with marble just might work!

Thanks.
Mark

 

[mingaun]

I have found a website that gives information for the dilution using 300ml of working solution. My paterson recommends 290ml. Will there be any harm if i make the working solution to 300ml instead? My developing tank is meant for one 35mm reel only.

 

[heespharm]

I have found a website that gives information for the dilution using 300ml of working solution. My paterson recommends 290ml. Will there be any harm if i make the working solution to 300ml instead? My developing tank is meant for one 35mm reel only.

no there isn't..

you can also just add 300ml of water to test if this is ok...

 

[mingaun]

i tested it and it fills right up to the small hole of the cone. I am not sure if too much fluid there will be not much room for agitation.